In a three paragraph statement, the families made it clear they are not associated with the non-profit group that was formed following the December 2012 shooting inside the Newtown school that claimed the lives of 26 people, including 20 first-graders.

"We, the undersigned families of loved ones killed in the Sandy Hook School tragedy, wish to publicly state that we are not associated with or supported by the Sandy Hook Promise organization," the statement said.

"We wish only to provide clarification for the many generous donors that believe they are directly supporting the families at the center of this tragedy by contributing to the Sandy Hook Promise origination," the statement said.

The letter was signed by 11 families, including the parents of nine of the children killed during Adam Lanza's shooting rampage – Charlotte Bacon, Josephine Gay, Jesse Lewis, Ana Marquez Greene, James Mattioli. Emilie Parker, Jack Pinto, Jessica Rekos and Avielle Richman. The daughters of Principal Dawn Hochsprung and the family of teacher Victoria Soto also signed the statement.

HARTFORD — Tim McGraw is defending his decision to headline a Hartford concert to benefit a Sandy Hook group, responding to critics who call it a gun control fundraiser.

A concert at the XFINITY Theatre on July 17 featuring McGraw will benefit Sandy Hook Promise, the nonprofit group organized by...

HARTFORD — Tim McGraw is defending his decision to headline a Hartford concert to benefit a Sandy Hook group, responding to critics who call it a gun control fundraiser.

A concert at the XFINITY Theatre on July 17 featuring McGraw will benefit Sandy Hook Promise, the nonprofit group organized by...

(Associated Press)

Sandy Hook Promise issued a written statement in reaction to the families' comments that said, in part:

"Sandy Hook Promise is an independent, national non-profit organization led by several Sandy Hook family members who lost loved ones in the shooting on December 14, 2012. Our mission is to protect children and prevent gun violence by providing awareness, education and programs in the areas of mental health, mental wellness and gun safety.

The proceeds from this concert do not directly benefit any family or family foundation, including those families who lead Sandy Hook Promise. All proceeds benefit our non-profit 501(c)3 Foundation which funds our protection and prevention programs. These initiatives in turn will help hundreds of thousands of children and familiesacross the country. Though all our materials and fundraising options make this clear, we thank the families that signed the letter to reinforce to their donors that the proceeds benefit Sandy Hook Promise."

The Tim McGraw concert scheduled for July 17 at the Xfinity Theatre was controversial before the families' statement. Many gun-rights supporters have criticized McGraw for holding a fundraiser for a group that lobbied hard, although largely unsuccessfully nationally, to change gun laws following the massacre.

McGraw was forced to issue a statement as the backlash grew. The backup act, Billy Currington, pulled out of the show.

"Let me be clear regarding the concert for Sandy Hook, given much of the erroneous reporting thus far. As a gun owner, I support gun ownership," McGraw said in a statement.

"I also believe that with gun ownership comes the responsibility of education and safety -- most certainly when it relates to what we value most, our children. I can't imagine anyone who disagrees with that. The concert is meant to do something good for a community that is recovering," McGraw said.

A family members who signed the statement issued Wednesday said families have been getting inquiries from people asking if the proceeds from the McGraw concert will be going directly to them. they are not, said the family member who wished to remain anonymous.

"Sandy Hook Promise makes it seem in their press releases that they are representing all of the families and they do not," the family member said.

The public statement by some of the families reveals a split that has quietly bubbled under the surface since Sandy Hook Promise was formed, originally to lobby for stronger gun laws.

While some families of victims became heavily involved in the non-profit's mission, and in fact are now paid employees of the group, other families shied away from it. Some said they felt that the group was raising money for its specific cause off their dead children without their consent.

There also were complaints that the group was not making it clear that while some of the funds it received did go to the families much of it was to support the group's mission. Sandy Hook Promise raised more than $1.8 million in the year following the massacre but its fundraising has slowed down, records show. IRS records show it has a total of about $3 million.